Icap 7000 spectrophotometer

X-Ray Diffractometer (XRD) model XRD-700-Shimadzu was used to investigate the crystalline nature of prepared GO and composite material. The surface morphology of prepared material was characterized by scanning electron microscope (SEM) model SEM-JSM 7800F, Fourier transform infrared spectroscopy (FTIR) (Nicolet-5700, Themofinnigan, USA) was used to determine functionalities and UV-visible spectroscopy (UV-vis) (Lambda-35, PerkinElmer, USA) was used to determine the concentration of analytes before/after adsorption. Zeta potential model DLS (sizing), M3-PALS (zeta potential) was used to determine the charge on surface of material. BET (AutosorbiQ S/N: 14716090801 station: 1) analysis was used to check the surface area and pore diameter of prepared material. Raman analysis was performed using (DXR Raman microscope with a 780 nm filter, Thermo Scientific). The contact angle of the prepared materials was estimated using a standard contact angle apparatus (Ossila contact Angle Goniometer). Metals analysis was performed by ICP-OES model Thermo Scientific iCAP 7000 spectrophotometer. The GC/MS analysis was carried out using an Agilent 6900 gas chromatograph and an Agilent 5975 mass spectrometer (Agilent Technologies, US).

To determine the “pseudo-total” element content of the soil, the Hungarian Standard MSZ 21470-50 2006 was followed with slight modifications. The sample preparation procedure and the microwave digestion of 0.5 g of soil (<0.1 mm) in cc. HNO₃ and in cc. H₂O₂ (3:1 v v⁻¹) solutions are described in detail elsewhere [87 (link),88 (link)].
To determine the soluble (“plant-available”) element content of the soil, the MSZ 20135 [93 ] was followed. The sample preparation procedure and the extraction of 0.5 g soil (<0.1 mm) with Lakanen–Erviö (LE) solution (0.02 M H₄-EDTA in 0.5 M ammonium acetate buffer and 0.5 M acetic acid, pH 4.65; Lakanen and Erviö, 1971) is described in published articles [87 (link),88 (link)].
From the prepared (dried and ground to particles < 0.1 mm) plant samples, 0.5 g was loaded into the pressure-proof bombs of the microwave digester (Milestone Ethos Plus, Sorisole BG, Italy). To all samples, 5 mL of distilled cc. HNO₃ and 3 mL 30% (v v⁻¹) H₂O₂ (Scharlau, Barcelona, Spain) were added [87 (link)].
Elemental analysis of all soil or plant samples was conducted with the inductively coupled plasma optical emission spectrometry (ICP-OES) technique, applied on an iCAP 7000 spectrophotometer (Thermo Fischer Scientific, Waltham, MA, USA). For the calibration, a multielement standard solution (n = 2) was applied. All element analyses were performed with 4 replicates.